The rainy season is over for the most part in April. Increased spells of sunshine also mean clearer skies at night, with slightly colder nighttime temperatures: wrap up warm when camping on the trail. The difference between temperature highs and lows is increasing too: highs of about 66° F (19° C) and lows of about 41° F (5° C). You will have to allow for the heat and the cold when you pack for your hike on the Inca Trail this month.
Crowds & Costs
Crowds are on the increase on the Inca Trail from March/April onwards, but still much quieter than in the main high season of June through August, when there will be the maximum permitted quota walking the trail every day. The region's busiest time by far will be if Semana Santa, or Holy Week, which falls within April when Peruvians and South Americans take extended vacations. This will also be the time when prices for hotels and tours increase: sometimes to levels as great as or greater than the main high season. At other times, this is shoulder season: not the highest prices of the year and not the lowest either.
Where to Go
Any of the treks in and around Machu Picchu are perfect to walk again this month. Even if you are walking the Inca Trail, you may want to try one of the other many hikes in the region: see here for the best day hikes in the Sacred Valley. Be sure to stop off in Cusco, too, where Semana Santa celebrations are especially vibrant.
What to Do
This is among the best times of year on the Inca Trail for plant lovers, when the flora is at its absolute best after the wet season, and bedazzles with plenty of color. In fact, the landscape's palette is generally at its boldest right now, and photographers will relish this month for snapping that perfect Sacred Valley shot, with plenty of sun and a few sweeps of cloud, and before high season crowds arrive. Trekkers can take full advantage of the Machu Picchu region being largely dry and in bloom to take to trails like the Inca Trail, the Salkantay Trek or even trails within Machu Picchu itself such as the hike to Wayna Picchu.
Shoulder season is also a good time to tackle another way of approaching Machu Picchu such as the Inca Jungle Trek, which involves cycling, zip-lining, and rafting as a 4-day adventure tour build-up to Machu Picchu and is best at this time of year while water levels in the river remain high.
From April onwards for the rest of the year, if you wish to take the train from Cusco to Machu Picchu you can do so from Cusco's Poroy train station once more (this was not an option from January through March, when it was necessary to first get a bus to Ollantaytambo, then pick the train up from there).
The big event of the month, and one of the biggest of the year, is Semana Santa, otherwise known as Holy Week. This week-long celebration falls on the week leading up to Easter, and is sometimes in March but is also often in April. The gateway city to the Inca Trail, Cusco has perhaps the most interesting Semana Santa: they include, on the Monday of Holy Week, the festival of Señor de los Tremblores. This festivity honors the earthquake of 1650 which damaged Cusco: in celebration, a 'Lord of the Earthquakes' effigy is carried through the city.